1. Field of the Invention
The present invention relates generally to the field of building construction methods. More specifically the present invention relates to a method of placing and securing shingle sheets, whether in the form of individual shingles or groups of shingles, to a roof underlayment using a polyurethane adhesive rather than nails, resulting in stronger attachment and permitting more rapid, efficient and reliable installation. The preferred method of installing shingle sheets onto a sloped roof, such as a peaked roof, includes the steps of depositing at least one first line of the adhesive onto the underlayment substantially parallel to the roof lower edge, the first line being spaced upwardly from the roof lower edge a distance equal to or less than the width of one of the shingle sheets; placing a laterally adjacent to or laterally overlapping first series of shingle sheets firmly onto the at least one first line of adhesive so that the shingle sheets extend substantially to the roof lower edge; depositing at least one second line of adhesive onto the underlayment substantially parallel to the roof lower edge spaced upwardly from the first series of shingle sheets a distance equal to or less than the width of one of the shingle sheets; placing a laterally adjacent to or laterally overlapping second series of shingle sheets firmly onto the at least one second line of adhesive so that the second series of shingle sheets overlaps upper ends of the first series of shingle sheets. A first interconnecting line of adhesive preferably is deposited onto the upper ends of the first series of shingle sheets so that the overlapping portions of the second series are adhered to the first series upper ends. The second series of shingle sheets preferably is staggered relative to the first series. The second step is repeated until the roof is covered to the roof peak or upper end with multiple series of shingle sheets.
It is preferred that the adhesive be deposited in lines because this achieves maximum adhesion. Alternatively a series of discrete paddies of adhesive are deposited onto the underlayment, in place of the lines of adhesive. Still another alternative is depositing scattered or randomly located discrete paddies of adhesive over the entire sheet coverage area of the underlayment.
2. Description of the Prior Art
There have long been methods of securing shingles and shingle sheets onto roof underlayment systems. These methods have always involved driving nails or tacks through the shingles, through the underlayment and into underlying plywood sheets. Problems with these traditional shingle securing methods have been that they make new roof construction, or re-roofing, costly in man-hours and they result in marginally adequate and unreliable shingle attachment. Still another problem has been that a certain level of diligence and responsibility are required for securing shingle sheets with nails. Several nails are needed to hold down each shingle sheet, and these nails must be positioned appropriately relative to the sheet edges for proper anchoring, and all of the nails should be driven entirely into the roof so that the nail heads rest flat against the sheet for maximized strength and minimized play during high winds. Finally, diligence and responsibility must be exercised in driving the proper number of nails into each shingle sheet. Rushed, careless or inadequately skilled workers may not perform these tasks completely and thus may produce a roof which does not withstand wind requirements, which soon leaks, and which does not last for a warrantied time period.
A polyurethane adhesive such as POLYPRO AH160™ manufactured by POLYFOAM PRODUCTS, INC. has been used to adhere concrete and clay roofing tiles to underlayment. Yet the possibility of using this adhesive to secure shingle sheets has not been recognized in the roofing industry, and the industry appears to teach away from such a method. In a consensus document entitled FRSA & NTRMA MODEL TILE SPECIFICATIONS, System Three Mortar & Adhesive-Set Tile Applications Only; Mortar or Adhesive-Set Tile Specification, the Sheet Metal and Air Conditioning Contractors Association (FRSA) and the Florida Chapter of the National Tile Roofing Manufacturers Association (NTRMA) illustrate on page 34 the steps of roofing materials application. For securing base ply to plywood the use of roofing nails and flashings is shown, and for securing top ply headlap to base ply the use of asphaltic adhesive, rather than polyurethane adhesive, is shown.
It is thus an object of the present invention to provide a method of securing shingles or shingle sheets to building roofs which requires significantly fewer man hours and consequentially generates lower labor costs than nailing shingles and shingle sheets to roof underlayments.
It is another object of the present invention to provide such a method which fastens the shingles or shingle sheets to an underlayment with greater strength and wind resistance capability than conventional nail attachment methods do.
It is still another object of the present invention to provide such a method which requires minimal skill and which is less dependent for quality outcome upon the diligence and responsibility of the particular workers involved, and thus produces a roof of more reliable quality because shingle mounting essentially is either done right or not done at all.
It is finally an object of the present invention to provide such a method which produces a finished roof which has an attractive appearance and a long life in a wide variety of whether and climate conditions.